30 100 | = | 20 100 | × | 2 | w | ( | 1 | − | 40 100 | ) | ÷ | ( | 1 | − | 20 100 | × | 2 | w | ( | 1 | − | 40 100 | ) | ) |
| 方程两边同时乘以: | ( | 1 | − | 20 100 | × | 2 | w | ( | 1 | − | 40 100 | ) | ) |
30 100 | ( | 1 | − | 20 100 | × | 2 | w | ( | 1 | − | 40 100 | ) | ) | = | 20 100 | × | 2 | w | ( | 1 | − | 40 100 | ) |
30 100 | × | 1 | − | 30 100 | × | 20 100 | × | 2 | w | ( | 1 | − | 40 100 | ) | = | 20 100 | × | 2 | w | ( | 1 | − | 40 100 | ) |
30 100 | × | 1 | − | 30 100 | × | 20 100 | × | 2 | w | ( | 1 | − | 40 100 | ) | = | 20 100 | × | 2 | w | × | 1 | − | 20 100 | × | 2 | w | × | 40 100 |
3 10 | − | 3 25 | w | ( | 1 | − | 40 100 | ) | = | 2 5 | w | − | 4 25 | w |
3 10 | − | 3 25 | w | ( | 1 | − | 40 100 | ) | = | 6 25 | w |
3 10 | − | 3 25 | w | × | 1 | + | 3 25 | w | × | 40 100 | = | 6 25 | w |
3 10 | − | 3 25 | w | + | 6 125 | w | = | 6 25 | w |
3 10 | − | 9 125 | w | = | 6 25 | w |
| - | 9 125 | w | − | 6 25 | w | = | - | 3 10 |
| - | 39 125 | w | = | - | 3 10 |
3 10 | = | 39 125 | w |
39 125 | w | = | 3 10 |
| w | = | 3 10 | ÷ | 39 125 |
| = | 3 10 | × | 125 39 |
| = | 1 2 | × | 25 13 |
| w | = | 25 26 |
| w | = | 0.961538 |